Parallel robot has the advantages of high stiffness, fast speed, strong flexibility, light weight and so on. It is an important part of the industrial robot together with the serial robot. In recent years, with the wide application of parallel robots in food, medicine, electronics and other light industries, and the unparalleled advantages in material handling, packaging and sorting, it has become a new force for the growth of industrial robots.

Four degrees of freedom parallel robot Ningbo material technology and Engineering Research Institute Chinese Advanced Manufacturing Technology Research Institute of precision and advanced robotics team the latest design, 3T1R can achieve four degrees of freedom of movement, is one of the innovative design of low DOF parallel robot, its main characteristics are the same 2 branched revolute passive connection to the moving platform through, and each have 2 of the same branch of branched chain drive through the mobile side as installed on a base. To further analyze the mechanism characteristics, using screw theory to verify the kinematic characteristics of the number and the degrees of freedom of the mechanism, the position of the closed solutions are obtained according to the kinematics characteristic and the configuration characteristics of the mechanism, the mechanism of positive solutions of position closed solution of up to 8 sets of Solutions, the position inverse solution has at most 4 solutions. The results show that the simple kinematics analysis is one of the characteristics of this parallel robot. In addition, it has the characteristics of symmetrical configuration, large working space, fast speed and high positioning precision. Compared with the traditional parallel robot, it can achieve three directions of XYZ motion and a rotation around the Z axis, and the working space in the drive direction can expand according to the operation requirement, which increases the scope of the workspace.

Each branch of the parallel robot prototype adopts high precision linear motor stator and two rotor as the driving mechanism, simple structure and motor positioning precision can reach micron level, in addition, the carbon fiber composite material with high strength as the main material of branched and effectively reduce the weight of moving parts; control system using ABB drive, synchronous control through PowerLink bus; the algorithm of off-line trajectory planning based on kinematics, kinematics of the mechanism of the current prototype can reach XYZ in three directions of translation and rotation around Z axis direction, moving range were 0.3m, 1.2m and 0.2m, the maximum speed reached 1.6m/s, the terminal positioning accuracy is about 1mm, around Z axis of rotation can reach – 120 degrees, can be widely used in flexible packaging, sorting and other chemical processes, has a very good application Prospects.